1. Field of the Invention
The present invention relates to a variable valve open-and-closure timing changing apparatus to change an open-and-closure timing of either an intake valve or an exhaust valve during a driving of an internal combustion engine.
2. Description of the Related Art
Such a kind of variable valve open-and-closure timing changing apparatus described above indicates a rotary body which is drivingly revolved by means of a crankshaft and a changing mechanism, interposed between a camshaft to drive the intake valve or exhaust valve, to relatively revolve the camshaft to the rotary body so as to modify the open-and-closure timing of either the intake valve or exhaust valve.
A Japanese Patent Application First Publication No. Heisei 10-141024 published on May 26, 1998 exemplifies a previously proposed valve open-and-closure timing changing apparatus.
The previously proposed valve open-and-closure timing changing apparatus includes: a housing which is revolved together with a rotary body revolved by means of the crankshaft of the engine; a rotor which revolves together with the camshaft; a plurality of vanes projected radially from the rotor and to form a plurality of working. oil chambers within the housing; and oil pressure supply and draining device to supply and drain working oil into each of the working oil chambers so that the housing is relatively revolved to the rotor.
An axial inner side of the rotary rather than an end surface of the housing is attached onto the end surface of the camshaft and the housing is journaled to the camshaft.
Since, in the previously proposed valve open-and-closure timing changing apparatus, the rotor is attached at its axial inner side than the end surface of the housing onto the camshaft, it is necessary to attach the rotor onto the camshaft with an accuracy of a gap of a journal between the housing and the camshaft taken into consideration when the previously proposed valve open-and-closure timing changing apparatus is actually mounted onto the normally available internal combustion engine. It may, thus, be difficult to attach the rotor onto the camshaft.
In addition, since it is necessary to make an accommodation design to the attachment of the housing to the camshaft due to an axial extension of the end of the camshaft to journal the housing, it is difficult to attach the previously proposed valve open-and-closure timing changing apparatus to the normally available internal combustion engine.
It is, therefore, an object of the present invention to provide a variable valve open-and-closure timing changing apparatus which is designed to enable the whole apparatus to be easily attached to a normally available internal combustion engine.
The above-described object can be achieved by providing a valve open-and-closure timing changing apparatus for an internal combustion engine, comprising: a rotary body to be is revolved in synchronization with a revolution of the engine; a camshaft; a vane rotor relatively rotatably housed within the housing member, to be revolved together with the camshaft, and having at least one vane radially projected therefrom; at least one pair of advance angle and retardation angle chambers partitioned between the housing member and vane rotor by means of the vane; a hydraulic supply-and-draining device that supplies a working oil into either one of the pair of the advance angle chamber or retardation angle chamber while draining the working oil from the other of the pair of the chambers to achieve a relative rotation between the housing member and vane rotor; and a boss portion projected from one axial direction of the vane rotor toward an outside of the housing member or extended at the same position thereof.
The above-described object can also be achieved by providing a valve open-and-closure timing apparatus for an internal combustion engine, comprising: a rotary body to be is revolved in synchronization with a revolution of the engine; a camshaft; a housing member to be revolved together with the rotary body; a vane rotor relatively rotatably housed within the housing member, to be revolved together with the camshaft, and having at least one vane radially projected therefrom; at least one pair of advance angle and retardation angle chambers partitioned between the housing member and vane rotor by means of the vane; a hydraulic supply-and-draining device that supplies a working oil into either one of the pair of the advance angle or retardation angle chamber while draining the working oil from the other of the pair of the chambers to achieve. a relative rotation between the housing member and vane rotor; a boss portion projected from one axial direction of the vane rotor toward an outside of the housing member or extended at the same position thereof; and a lock mechanism including: a slide motion enabling hole disposed in the vane; a slide member to make a slide motion thereof within the slide motion enabling hole; a fit hole disposed in the housing member to which the slide member is enabled to be fitted; a biasing member to bias the slide member in a direction toward the fit hole; and a hydraulic passage to make the slide motion of the slide member in accordance with a hydraulic.